INTRODUCTION: Dentinogenesis imperfecta (DI) or hereditary opalescent dentin is an autosomal dominant disorder affecting both primary and permanent dentition. Early diagnosis and treatment of DI is important for normal facial growth and esthetic continuity by preserving occlusion and tooth structure. It also provides psychological motivation by increasing the patient's quality of life. Providing functional dentition in DI patients prevents loss of the vertical dimension, while enabling normal growth of the facial bones and jaw joint.CASE REPORT: A 20-year-old male with DI was referred to our clinic with chewing difficulty and esthetic and speech problems. His brother also had this disease. Oral examination showed the loss of many teeth and the absence of enamel on most of the remaining teeth, causing discoloration and exposing soft dentinal tissue with calcification disorder. Despite widespread attrition of the teeth, pulp chambers were not exposed. The tip of the lower jaw was prominent in the patient's profile. Placing metal-ceramic fixed dentures in the lower jaw and an overdenture prosthesis in the upper jaw improved the patient's psychological state as well as his function, phonation, and esthetics.CONCLUSION: This case report presents the intraoral findings in a patient with DI, including the histopathological findings, and the prosthetic treatment approach and the treatment outcome.